2690 



Journal of Applied Microscopy 



LXXVIII. AUsma plantago L. Water Plantain. 



Class, Monocotyledones. Order, Naiadales. Family, Alismaceae. 



The water plantain is common in wet and muddy places, on the margin of 

 ponds and creeks. Herbarium specimens and preserved material may be used. 



Sporophyte. 



1. Sketch a leaf and a part of the inflorescence. 



2. Sketch a flower showing the four sets of floral organs — calyx, corolla, 

 androecium and gynoecium. How many sepals, petals, stamens and carpels ? 

 Are the parts spiral or cyclic ? Free or united ? Is the flower monosporangiate 

 or bisporangiate ? Note that the flower is hypogynous. What advance does this 

 fiower show over that of Sagittaria or Ranunculus ? 



Fig. 14.— Diagram of life cycle of Angiosperm (Alisma). 



3. Make a diagram of the flower. See Fig. 15 a. 



4. Cut cross sections of the stamens and draw under low power. How 

 many microsporangia (pollensacs) ? Cut open the ovulary and dissect out the 

 ovule (megasporangium). Draw. 



5. From prepared slides draw a microsporocyte and a microspore, showing 

 the nucleus, cytoplasm and wall. 



6. From prepared slide draw a young ovule, showing the funiculus, the 

 integuments, the megasporangium proper (nucellus), and the single megaspore. 

 Note the absence of a wall around the megaspore. Why not present ? 



Gametophytes. 



7. From prepared slide draw a male gametophyte (pollengrain), showing 

 the tube nucleus and the two elongated sperm cells. 



